Vehicle drivelines include at least one driveshaft that is used to transmit power from a vehicle engine and transmission to a single drive axle or tandem drive axle. Typically, heavy-duty vehicles, such as large trucks, include more than one driveshaft as a result of having a long wheelbase, and/or use of a tandem drive axle. At each end of a driveshaft, universal joints (U-joints) are used to connect the driveshaft to the next driveline component. For example, U-joints can be used to connect one driveshaft to another driveshaft or can be used to connect a driveshaft to a drive axle component.
The U-joint allows two driveline components to be oriented at different angles relative to each other to accommodate relative movement and angular misalignment while transmitting torque between the two driveline components. Further, as drive axles cooperate with a vehicle suspension to dampen shocks from rough road conditions, U-joints provide flexibility to allow the adjoining driveline components to move relative to one another
Typically, each U-joint includes a center body member with four (4) trunnions that extend outwardly from the center body member to form a shape of a cross. The U-joints also include two yokes that each have two bore locations at diametrically opposed positions. The yokes are each mounted to two of the trunnions. The combination allows the two yokes to move angularly relative to each other with respect to the center of the cross member. A cup and bearing assembly is mounted on an end of each trunnion. The cups are coupled to the yokes.
In order for the U-joint to operate properly over long periods of time, it is important to have good lubrication. The center body member typically includes an external grease fitting that is in fluid communication with each trunnion via internal grease grooves or channels. The cup and bearing assembly receives lubrication through the grease grooves. The cup and bearing assembly includes a seal assembly that seals the grease within the center body member.
There are several disadvantages with current seal assemblies. One disadvantage is that current seal assemblies do not always provide sufficient protection from external contaminants. External contaminants that enter the cup and bearing assembly can damage bearing components resulting in premature wear of the U-joint. Another disadvantage is that seal longevity directly depends on regular replacement of lubrication, which is time consuming and difficult to provide as frequently scheduled service and maintenance operations cause vehicle downtime.
Another disadvantage with current cup and bearing assemblies relates to assembly and handling of cups to the trunnions. Once the cups are assembled onto the trunnions, a wire is required to hold the cups in place until the center body member can be assembled onto the yokes. This requires additional assembly time and material.
Thus, there is a need for a universal joint assembly that does not require a separate retaining wire, and which includes improved sealing characteristics, in addition to overcoming other above-mentioned deficiencies in the prior art.